1. Field of the Invention
The present invention relates generally to the field of ophthalmics, more particularly to ophthalmic devices, and still more particularly to dual intraocular (IOL) lens systems and associated instruments for the implanting of the same.
2. Background Discussion
At the onset it may helpful to the understanding of the present invention to define the terms xe2x80x9cphakicxe2x80x9d and xe2x80x9caphakicxe2x80x9d as relate to human eyes. The term xe2x80x9cphakicxe2x80x9d is applied to an eye in which the naturals ocular lensxe2x80x94whatever its conditionxe2x80x94has not been removed. In contrast, the term xe2x80x9caphakicxe2x80x9d is applied to an eye from which the natural ocular lens hasxe2x80x94for any reason-been removed. In this regard, a phakic eye is considered a dynamic or active eye because the natural lens is subject to change over time. In contrast, an aphakic eye is considered a static eye because the natural lens has been removed.
Vision in an eye is enabled by the cornea and the natural lens (and/or an implanted IOL) located posterior of the cornea, both or all of which refract light from a viewed image to the retina of the eye.
One serious and relatively common vision problem is reduced or complete loss of sight due to the natural ocular lens becoming cloudy or opaquexe2x80x94a condition referred to as cataract. The formation of cataracts is most often associated with natural bodily aging processesxe2x80x94perhaps caused or aggravated by long-term exposure to ultraviolet rays from the sun. In any case, most individuals over the age of about 60 years suffer from cataracts at least to some extent.
The current state of ophthalmics, as far as is known to the present inventor, is that cataracts cannot be cured or reversed, nor can the cataract formation process be significantly arrested. Consequently, when a natural lens becomes so cloudy by cataracts (or by any other mechanism) that the lens can no longer effectively refract light from a viewed image to the retina, thereby significantly impairing vision, the corrective action involves the surgical removal of the natural lens. In this manner, a phakic eye becomes an aphakic eye.
After the defective natural lens has been surgically removed, the common current practice is to implant in the individual""s aphakic eye an artificial lens called an intraocular lens or IOL. Previously, thick, high diopter spectacles were prescribed for aphakic eyes, such spectacles however being generally disliked by most patients for obvious reasons.
Intraocular lenses are constructed from biocompatable optical materials and are, to the extent possible, configured to provide the optical characteristics (with the current exception of accommodation) of the removed natural lens in its prior healthy condition.
IOLs are generally considered to have become practical as a result of the World War II discovery by Dr. Peter Ridley that shards of damaged British fighter aircraft canopies made of PERSPEX (i.e., PLEXIGLAS)xe2x80x94an optically clear, hard poly-methyl methacrylate (PMMA) plastic materialxe2x80x94embedded in pilots"" eyes caused no adverse reaction in the eyes.
As a result of this discovery, hard, rigid IOLs were constructed from an optical grade of PMMA. These rigid IOLs were compatible with then-current surgical procedures used for removing natural lenses in one piece. That is, the PMMA IOLs could be implanted through the relatively large, 5-6 mm, ocular incisions made for removal of the natural lenses.
Subsequently in the early 1970""s Dr. Charles Kelman developed a lens-removal procedure utilizing ultrasound to break up natural lenses. This enabled the natural lenses to be extracted with an irrigating fluid in an emulsified condition from the eye through a much smaller ocular incision than that previously needed to extract the natural lens in one piece. This advantageously resulted in reduced patient trauma and patient recovery time.
This new surgical procedure, called phacoemulsification, created a need for elastically-deformable IOLs that could be rolled or folded for insertion into the eye through the same small ocular incision used in the phacoemulsification lens removal procedure, and which then unfolded to their original shape once in the eye. Such deformable IOLs are commonly constructed from an optically clear, high refractive index, biocompatable silicone or acrylic material.
In addition to the implanting of IOLs in aphakic eyes to restore vision after removal of the natural lens, there has recently been an interest in implanting IOLs in phakic eyes to correct vision deficiencies even with healthy natural lenses. The implanting of IOLs in phakic eyes is an often-attractive alternative to some individuals to the wearing of corrective spectacles or contact lenses or having such corneal surgical procedures as radial keratomy (RK) or photo-radialkeratectomy (PRK) performed.
In an aphakic eyes, an IOL is now most commonly implanted in the posterior chamber of the eye in the general location from which the natural lens was removed. Nevertheless, the implanting of an IOL in the anterior chamber is sometimes necessary because, for example, of damage to the posterior wall of the capsular bag during removal of the natural lens. In contrast, an IOL for a phakic eye is most commonly implanted in the anterior chamber of the eye, but may sometimes be implanted in the posterior chamber or on top of the natural crystalline lens.
Regardless of the reason for the implanting of an IOL or the location of the implanted IOL, a principal objective of the present invention is to provide an IOL system in which corrections to IOL spherical, cylindrical and/or add power can be easily made with minimal invasive action.
In accordance with the present invention, there is provided a corrective intraocular lens system which comprises a primary intraocular lens for implanting into an individual""s aphakic or phakic eye and a thin, elastically deformable, corrective secondary intraocular lens.
The primary intraocular lens includes an optic portion having an optical axis and an anterior surface and a posterior surface, and includes attachment means for maintaining the optic portion optical axis centered along the optical axis of the individual""s eye. The primary IOL optic portion is formed having a narrow recess or groove region formed into the anterior surface adjacent to peripheral regions of the optic portion.
The secondary IOL has an optic portion with an anterior surface and a posterior surface. An edge region of the secondary intraocular lens is formed to fit into the primary intraocular lens recess region so that the posterior surface of the secondary intraocular lens lies along the anterior surface of the primary intraocular lens and is sized for inserting into an individual""s eye through an ocular incision no greater than about 2.5 millimeters. The secondary intraocular lens is formed from an elastic material such as a silicone or acrylic material.
In accordance with a preferred embodiment of the invention, the primary intraocular lens recess region has a width of about 0.2 mm and a depth of about 0.2 mm to about 0.9 mm. In a variation embodiment, recess region of said primary intraocular lens is formed having a concave upper surface and a concave lower surface. In another, the recess region of the primary intraocular lens is formed having an overhang region with a uniform thickness. The recess region of the primary intraocular lens may extend all or only partially around the primary intraocular lens optic.
The primary intraocular lens preferably has a spherical diopter power between about xe2x88x9210 and about +35, a cylindrical diopter power between about 0.0 and about +10.0, and/or an add diopter power between about 0.0 and about +4.0. Further, the primary intraocular lens may be a posterior chamber intraocular lens or the optic thereof may be configured for implanting in the anterior chamber of an eye.
It is preferred that the secondary IOL has a spherical diopter power between about xe2x88x923.0 and about +3.0, a cylinder diopter power between about xe2x88x925.0 and about +5.0, and/or an add diopter power between about +1.0 and about +4.0. Further, the secondary intraocular lens preferably has a center thickness between about 0.1 mm and about 0.2 mm, and the edge attachment region of the secondary IOL may extend at least substantially around the periphery of said secondary intraocular lens or may comprise at least one radially extending tab preferably formed having at least one transverse groove defining a bend line. In any event the secondary intraocular lens is preferably formed having at least one positioning hole formed in the edge attachment region.
Individually, there is provided an intraocular lens for implanting into an individual""s aphakic or phakic eye. The intraocular lens comprises an optic portion having an optical axis and an anterior surface and a posterior surface, and includes attachment means for mained training the optic portion optical axis centered along the optical axis of the individual""s eye. The optic portion is formed having a narrow recess region formed into the anterior surface adjacent to peripheral regions of the optic portion.
The recess region is configured for receiving an edge region of a thin, flexible corrective intraocular lens and thereby detachably attaching the corrective intraocular lens to the intraocular lens to provide power correction thereto.
Preferably, the intraocular lens recess region has a width of about 0.2 mm and a depth of about 0.2 mm to about 0.9 mm. The intraocular lens recess region may be formed having a concave upper surface and a concave lower surface or having an overhang region of uniform thickness. In addition, the intraocular lens recess region may extend around the intraocular lens optic.
The intraocular lens may have a spherical diopter power between about xe2x88x9210 and about +35, a cylindrical diopter power between about 0.0 and about +10.0, and/or an add diopter power between about 0.0 and about +4.0.
Further, the intraocular lens optic may be a posterior chamber intraocular lens or the optic of the intraocular lens may be configured for implanting in the anterior chamber of an eye.
Further comprising the system may be a secondary IOL handling device which includes an elongate, slender pin having means for engaging a secondary intraocular lens and control means connected for rotating the pin in a first rotational direction causing the secondary intraocular lens to become wrapped around said pin and for rotating the pin in a second rotational direction causing a secondary intraocular lens wrapped around the pin to unwrap from the pin.
Included in the handling device is an elongate, thin shield and means connected for axially moving the shield between a first, extended position in which at least portions of the shield extend over a secondary intraocular lens wrapped around the pin and a second, retracted position in which the shield does not extend over a secondary intraocular lens wrapped around the pin. The shield is formed from a biocompatible, elastomeric material, preferably a silicone material.
At least portions of the shield are generally semicylindrical in shape and side edges thereof are preferably flared outwardly.
The means for engaging a secondary intraocular lens includes a protuberance formed on the pin, the protuberance being located and sized to fit into a positioning hole formed in the secondary intraocular lens.
There is also individually provided an elastically deformable intraocular lens having an optic portion with a convex anterior surface and a concave posterior surface, such intraocular lens having an overall dimension not exceeding about 7 mm and a center thickness not exceeding about 0.4 mm. The elastically deformable intraocular lens is formed having a peripheral edge attachment region sized to fit into a narrow recess region formed in a primary intraocular lens optic. This causes the posterior surface of the elastically deformable intraocular lens to lie along an anterior surface of the primary intraocular lens optic so that the elastically deformable intraocular lens provides a power correction to the primary intraocular lens optic.
The elastically deformable intraocular lens is formed for inserting into an individual""s eye through an ocular incision no greater than about 2.5 millimeters and may be formed from a silicone material or from an acrylic material. Further, the elastically deformable intraocular lens may have a spherical diopter power between about xe2x88x923.0 and about +3.0, a cylinder diopter power between about xe2x88x925.0 and about +5.0 and/or an add diopter power between about +1.0 and about +4.0.
The elastically deformable intraocular lens preferably has a center thickness between about 0.1 mm and about 0.2 mm and the edge attachment region extends at least substantially around the periphery of the elastically deformable intraocular lens. Alternatively, the edge attachment region may comprise at least one radially extending tab, and the tab may be formed having at least one transverse groove defining a bend line. There may be included at least one positioning hole formed in said edge attachment region.
There may individually be provided a handling device for implanting a thin intraocular lens into and extracting a thin intraocular lens from a patient""s eye. The handling device comprises an elongate slender pin having means for engaging a thin intraocular lens; and means connected for rotating the pin in a first rotational direction to cause an engaged intraocular lens to become wrapped around the pin and for rotating the pin in a second rotational direction to cause an intraocular lens wrapped around the pin to become unwrapped from the pin.
Included is an elongate thin shield and means connected to the shield for moving the shield between a first axial position in which at least regions of the shield extend over an intraocular lens wrapped around the pin and a second axial position in which the shield does not extend over an intraocular lens wrapped around the pin.
Further included in the present invention is an instrument for attaching a secondary intraocular lens to a primary intraocular lens, the secondary intraocular lens having an attachment edge region and the primary intraocular lens having an angled, annular recess for receiving the secondary intraocular lens attachment edge region, the annular recess having a flexible, overhanging outer lip. The instrument comprises a slender ocular insertion portion having an open distal end and preferably having a major cross sectional dimension not greater than about 2 mm.; a lever having a finger portion extending to one side; and operating and control means connected to the lever for causing axially movement of the lever beyond the insertion portion open distal end.
Included in the instrument is a slender, substantially rigid post extending forwardly from said open distal end of the ocular insertion portion, the lever being axially slidably mounted on the post. The post terminates in a flared head region for limiting axial extension movement of the lever along the post.
The lever is constructed from an elastomeric material, preferably a silicone or acrylic material, and the operating and control means, which include an axially movable pin pivotally connected to the lever finger portion, are operative for causing the forward flexing of the lever finger portion when axial forward extension movement of the lever along the post is stopped by the lever abutting the flared head region of the post, thereby enabling the finger portion to lift the outer lip overhanging the recess.
It is preferred that the post be connected to a transverse member that is axially fixed relative to the ocular insertion portion. Second operating and control means are connected for causing a sidewardly angular movement of between about 45xc2x0 and about 90xc2x0 of the lever relative to a longitudinal axis of the ocular insertion portion. The second operating and control means include an axially movable pin connected to a side region of the transverse member. Also, a lens edge pushing member is fixed to a side region of the transverse member.
More specifically, the instrument for attaching a secondary intraocular lens to a primary intraocular lens comprises a slender ocular insertion portion having an open distal end; a slender, substantially rigid post extending a fixed distance forwardly from the open distal end, the post being connected to a transverse member that is axially fixed relative to the ocular insertion portion; and an elastomeric lever slidingly mounted on the post, the lever having a finger portion extending to one side of the post.
Included are first operating and control means connected to the lever for causing axially movement of the lever along the post with concomitant axial movement of the finger portion, the first operating and control means including an elongate pin having a distal end pivotally connected to the lever finger portion. Further included are second operating and control means connected for causing a sidewardly angular movement of between about 45xc2x0 and about 90xc2x0 of the post and the lever mounted on the post relative to a longitudinal axis of the ocular insertion portion, the second operating and control means including an elongate pin connected to a side region of the transverse member.
The post terminates in a flared head region for limiting axial extension movement of the lever along the post, the first operating and control means being connected to the lever for causing the forward flexing of the finger portion when forward movement of the lever along the post is stopped by the lever abutting the flared head region of the post. An intraocular lens edge pushing member is fixed to a side region of said transverse member.
The flexible tip portion of the attachment instrument of the present invention importantly enables the instrument to be used to install different edge regions of a secondary intraocular lens to a recess in a primary intraocular lens by simply repositioning the instrument in a single ocular microincision no larger than about 2 mm.
There is also provided a primary intraocular lens having an angled, annular recess for receiving a secondary intraocular lens attachment edge region, the annular recess having a flexible, overhanging outer lip that is generally wedge shaped, a free end of the lip being substantially thicker than the region adjacent the bottom of the recess. The free end of the overhanging lip has a concave surface shaped for refracting incident light away from a focal point of the lens.